Digital Electronics and File Management Unit D

Objectives Introduce Digital Data Representation Introduce Integrated Circuits Explore Microprocessor Performance Factors Understand Computer Memory: RAM Explore Computer Memory

Objectives Introduce Computer File Basics Understand File Locations Explore File Management Understand Logical File Storage Use Files Understand Physical File Storage

Digital Data Representation The form in which information is conceived, manipulated and recorded on a digital device. Uses discrete digits/electronic signals -1,0 (bits - binary digits) -On/Off -Yes/No Byte = 8 bits = 1 character

Coding Systems Depends on computer ASCII (7 bits) Extended ASCII (8 bits - current PCs) EBCIDIC (8 bits - older IBM machines ) Unicode (16 bits - good for languages - future)

Quantifying Bytes and Bits Bit = b Nibble = Half of a byte Byte = B Kilobyte (KB) (1024 bytes) Megabyte (MB) (Million bytes) Gigabyte (GB) (Billion bytes) Terabyte (TB) (Trillion bytes)

Integrated Circuits A super thin slice of semi–conducting material packed with microscopic circuit elements such as wires, transistors, capacitors, logic gates, and resistors. Bits are represented as electrical pulses that travel over these circuits. Also called a chip, microchip and computer chip.

Integrated Circuit Uses MicroprocessorsMemory Support circuitry ChipPackage

Microprocessor Packages DIPs (dual in-line packages) DIMMs (dual in-line memory modules) PGAs (Pin-grid arrays) SECs (single-edge contact cartridges)

Microprocessor (Processor) Designed to process instructions Largest chip on motherboard Intel: world’s largest chipmaker (Pentiums) AMD: Cheaper chips (Athlons)

Motherboard Main circuit board

Microprocessor Components

Microprocessor Performance Speed: microprocessor clock set clock speed (MHz or GHz ) World Size: number of bits the microprocessor can manipulate at one time (32-bit or 64-bit) Cache: high speed memory (kilobytes)

Microprocessor Performance Instruction Set Type: –CISC (Complete instruction set computer) –RISC (Reduced instruction set computer) Processing Technique: –Serial –Pipelining –Parallel Look at benchmark testing to compare

Memory Types Random Access Memory (RAM) Virtual Memory Read-Only Memory (ROM) CMOS

RAM Temporary (volatile) holding area for data, application software and operating system Expensive chip set Circuitry Less storage than disk Capacitors hold bits Capacity measured in MB ( MB) Speed in nanoseconds Random Access Memory

RAM Types SDRAM –Synchronous Dynamic RAM –fast and cheap –DIMMS RDRAM –Rambus Dynamic RAM –faster and more expensive –RIMMs AND SO-RIMMs

Virtual Memory Disk based Stores parts of programs and data until they are needed by the processor Works with RAM, but is slower

ROM Permanent on a chip from manufacturer Holds computer start up routine, which are hard-wired instructions PROM: programmable via “burning” EPROM: erasable ROM BIOS (basic input/output system) Read-Only Memory

CMOS Battery powered More permanent than RAM; less permanent than ROM Stores basic computer configuration Must be updated via CMOS setup program when configuration changed Complementary Metal Oxide Semiconductor

Computer File Characteristics A collection of data on a storage medium Filename conventions Filename extension.txt.txt.jpg.jpg.exe.exe.doc.doc

File Locations Device drive letters A: C: D: Directory –Root Directory (C:\) –Subdirectory or folder (C:\Documents) –File specification or Path –File size and date Filename extensionFilename Secondary folder Primary folder Drive letter C:\Music\Reggae\Marley One Love.mp3

Deleting Files Move to Recycle Bin in Windows Undelete Empty Bin

File Management Helps you organize your computer files File/Save and File/Open Utilities like Windows Explorer or MAC Finder –list, find, move, copy, delete, rename Save vs. Save As

Logical File Storage Filing cabinet model Metaphor to help you visualize files on a storage device Windows Explorer Folder hierarchy

Using Files Start application (open Word) Create file (type text) Save file (File/Save) Close file and application (File/Exit) Open file again for editing (File/Open) Edit file Save file –File/Save –File/Save As

Physical File Storage Storage medium formatted into tracks /sectors electronically File system keeps track of names and file locations. –Windows uses FAT32 OR NTFS Clusters: a group of sectors that speeds up storage and retrieval

Physical File Storage FAT (File Allocation Table) on each disk keeps track of where all files are and which clusters are empty. If damaged, you lose everything. Defragmentation Utility rearranges files to be stored in contiguous clusters.

Tech talk: How a microprocessor executes instructions Complex task broken down into a series of simple steps or instructions Instructions are in machine code (0s and 1s) and consist of: –Op code: Operation code like Add, Compare, etc –Operand: data address for operation

Tech talk: How a microprocessor executes instructions Instruction Set is built into processor Instructional Cycle is the execution of a single instruction Fetch Instruction Interpret Instruction Execute Instruction Increment Instruction Pointer

Issue Who invented the computer?

Digital Electronics and File Management End